uh.... that's annoying. Lots of softwares alows you to use Shift + scroll to do that. But in Houdini, the best I can find is puting your mouse on the horizontal bar and scroll. ...but that's about the same as a click and drag...
Considering that cells are wider than they are tall, you might be better off using the Filter in the top right of the panel, if you're looking for specific attributes
I know it is only useful for very specific scenarios, but if you are working with a few vectors or arrays, you don't need many before they start stacking up horizontally. But in those scenarios it would be certainly comfortable.
